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> Subjectively, I see no point in having "val", "var", "let", "def", "fn" symbols which bring only noise to code. Usually, the reason is to make parsing easier

> Subjectively, I see no point in having "val", "var", "let", "def", "fn" symbols which bring only noise to code. Usually, the reason is to make parsing easier. C++ is infamous for having undecidable grammar. Ruby is extremely pleasing to the eye, but its grammar is a clusterfuck. Newer languages have learned from that, so they try to have simpler grammars. Another reason for those small syntax markers is to avoid implicit language decisions. In Rust, having to write one of "let/let mut/const" means forcing the programmer to make an explicit choice regarding mutability and memory usage. In Scala, "val/lazy val/var/lazy var/def" means having to think about mutability and evaluation times. > What about Rust unable to drop parenthesis after a function? In the case of Rust, the reason is uniformity. Even Scala, of all languages, is walking back on the optional parentheses, because the language allows to define functions with multiple argument lists, and optional parentheses introduce ambiguity between functions with empty argument lists and functions with no argument lists.

tastyminerals2 6y ago
Yes, "make an explicit choice regarding mutability" can be done even easier by actually writing "immutable double[] arr = [1, 2, 3];", "const double[] arr = [1, 2, 3];". See, no Scala val/var which to a person who doesn't know the language tell nothing. When the language grammar is unambiguous and coherent you have faster compiling times and occasionally better readability. D hits a nice spot in here by capitalizing on C++ mistakes. "optional parentheses introduce ambiguity" -- true, they do. However, I am struggling to understand why it is necessarily a bad thing? For a user I see a clear convenience of being able to write "double[] zeroArr = arr.zeros;" or "double[] newArr = 6.iota.sliced(3, 2).array.reverse.dropOne.join;". And if that is not enough, you can also inject your custom method into this chain and it will just work. Don't know about Rust but Scala simply refuses to compile in such cases which for a functional language looks like a limitation. These are the D features that I really enjoy.

tastyminerals2 6y ago

Yes, "make an explicit choice regarding mutability" can be done even easier by actually writing "immutable double[] arr = [1, 2, 3];", "const double[] arr = [1, 2, 3];". See, no Scala val/var which to a person who doesn't know the language tell nothing. When the language grammar is unambiguous and coherent you have faster compiling times and occasionally better readability. D hits a nice spot in here by capitalizing on C++ mistakes. "optional parentheses introduce ambiguity" -- true, they do. However, I am struggling to understand why it is necessarily a bad thing? For a user I see a clear convenience of being able to write "double[] zeroArr = arr.zeros;" or "double[] newArr = 6.iota.sliced(3, 2).array.reverse.dropOne.join;". And if that is not enough, you can also inject your custom method into this chain and it will just work. Don't know about Rust but Scala simply refuses to compile in such cases which for a functional language looks like a limitation. These are the D features that I really enjoy.